A CH-47 Chinook helicopter, like this one used for training, was shot down by the Taliban in Afghanistan, killing all aboard. A special-operations officer questions the use of the craft for such “hot-LZ” purposes. (U.S. Navy photograph via Associated Press) more >

Three U.S. families filed a lawsuit Tuesday against Afghan President Hamid Karzai and his security forces, accusing them of betraying their sons in the Aug. 6, 2011, helicopter shoot-down that killed 30 Americans, 17 of them Navy SEALs.

The families of three of the dead Americans accuse Mr. Karzai of corrupt practices that include taking bribes from Iran for the deaths of the U.S. service members.

The lawsuit states that a group of Afghan officials called the Operation Coordination Group, which approves U.S. strike missions, leaked details that reached the Taliban.

The helicopter — a CH-46D Chinook with the call sign “Extortion 17” — was shot down by Taliban fighters stationed about 150 yards from a landing zone never before used by U.S. forces in Afghanistan’s Tangi Valley. The SEALs and their support personnel were members of SEAL Team Six, the unit that killed Osama bin Laden in May 2011.

Filed in U.S. District Court in Washington, the lawsuit says the Obama administration put a target on the unit’s back by publicly disclosing many details about the bin Laden mission.

The families’ lawsuit, which seeks $600 million in damages from Afghanistan and another defendant, Iran, was filed by Freedom Watch and its director, Larry Klayman.

Mr. Klayman said the plan is to use the legal action as a vehicle to demand disclosures from the Defense Department about how the mission was conducted — something Congress is unwilling to do, he said.

“We’re going to take discovery and leave no stone unturned,” said Mr. Klayman.

The watchdog lawyer over the years has filed a number of lawsuits that have forced the U.S. government to disclose information.

“We’re going to focus in on the Defense Department,” he said.”We’re going to use the case as an opportunity to get answers and also to get justice … We have Afghan officials in this country and we can approach them here.”

“We believe the lawsuit will show Hamid Karzai and Afghanistan were responsible for killing the sons of our clients. They gave up the coordinates and vital information about the mission. It was a payback to the Taliban, al Qaeda and Iran for the death of bin Laden.”

The suit was brought by Charles and Mary Strange, the father and step-mother of Navy cryptologist Michael Strange; Douglas and Shaune Hamburger, parents of Army National Guardsman Patrick Hamburger; and Phouthasith Douangdara, whose son, John Douangdara was a Navy special warfare specialist who handled a warrior dog on the mission.

Several family members have said they believe their sons were the victims of a set-up. They point to the fact the Taliban fighters had stationed themselves with rocket-propelled grenades in a tower close to the landing zone. At the time, the Taliban had launched a successful campaign to persuade Afghan security personnel to turn on Americans and killed them in so-called insider attacks.

A senior Pentagon special operations official told a House subcommittee last month that officials do not believe the “Extortion 17” mission was compromised.

The SEALs, support personnel and eight Afghan troops were loaded hurriedly on the Chinook that night as a backup force for 47 Rangers who had been in the valley for over three hours hunting for a senior Taliban leader.

The U.S. command originally called the SEAL insertion a rescue mission. But evidence later showed the Rangers were not in trouble and just wanted help chasing “squirters” — Taliban trying to flee.

The lawsuit notes Mr. Karzai’s increasingly anti-American statements and actions, including conducting secret talks with the Taliban, denigrating the U.S. war effort, refusing to approve an agreement to keep NATO forces in the county after the end of the year and moving to release captured terrorists who pose a threat to U.S. service members.

“Defendant Iran finances and provides other things of value to Defendant Karzai and his agents in the Afghan government, military, terrorists and terrorist groups in exchange for compromising the security and paying for the deaths of Plaintiffs’ decedents,” the lawsuit charges.

The suit describes the alleged plot:

“Defendant Karzai is known internationally as criminally corrupt and upon information and belief, compromised Navy SEAL Team VI’s and other special operations servicemen’s mission, Extortion 17, to pursue the Taliban leader, Qari Tahir, by selling the coordinates of the SEAL’s location and/or other classified information to terrorist organizations, Defendant Taliban and Defendant Al Qaeda, for large sums of money.”

It adds: “He personally engaged in concert with terrorists and terrorist groups in a criminal enterprise designed to enrich him personally. Defendant Karzai solicits and accepts money and other things of value from terrorists and terrorist groups in exchange for compromising the security and planning for the deaths of Plaintiffs’ decedents.”